New process for the coloration of synthetic materials and the industrial products resulting therefrom



NEW PROCESS FOR THE COLORATION F SYN-' THETIC MATERIALS .AND THE INDUSTRIAL.

j PRODUCTS RESULTING THEREFROM;

Joseph Khachoyan, Chantilly, and Jean-Paul Nieder nets resulting therefrom. i The colouration by dyeing or by printing of synthetic fibres based on polyacrylonitrile gives-riseto difliculties.

At present, some particular members of f'different classes of dyes give results which can be made use of in industry namely; plastosoluble dyes, vat dyes, basic dyes, in-

soluble azo dyes formed on the fibres and acid dyes ap,-"

plied according to the cuprous ion process. Their application can be effected at 100C. or ata higher terne perature; application above IOO C. results in an irnprovement of the penetration, uniformity, speed of dyeing,

and sometimes the yield of these dyes. Nevertheless, it

has not been possibleto extend the use of this method and'therefore to enlarge the range of dyes which can be employed to colour products based on polyacrylonitrile Another solution has been proposed fo'r this purpose.

It consists in making copolymerscontaining, besides acrylonitrile, products capable of facilitating 'the dyeing or printing by-loosening'the internal structure of the fibre or providing chemical functions on which certain dyes can become fixed.

Finally, in French Patent No. l,O94,620 there is described a process for dyeing fibres based on polyacrylonitrile which COHSiStS'iH using the copper complexes of o:o-dihydr0xy monoazo dyescontaining only one sul-' phonic group, in the presence ofhydroxylamine sulphate. It has now been found that the products 'of'polymerisa tion or copolymerisation; of acrylonitrile or vinylidene' cyanide can be dyed in strong shades by means of dyes which are soluble or insoluble in water, other than those of the above-mentioned French Patent, by operating without copper salt in the presence of hydroxylamine in the free state or in the form of a'salt thereof, at a temperature above 100 C. The tinctorial yield is, in-general, superior to that which is obtained by first treating the fibre with hydroxylarnine (for example, according to the process of US. Patent No. 2,792,276) or by carrying out the dyeing in the presence of hydroxylamine at a temperature below 100 C.

. The products of polymerisation or copolymerisation of acrylonitrile or vinylidene cyanide may be in various forms such as, for example, fibres, threads, coarse fibres, fabrics or sheets. In view of this, they are on occasion treated with other products e.g. productsresulting from a polymerisation, or mineral or organic products intended to modify the physical properties of the substance or its physical appearance. Certain copolymers may contain products whose object is either toloosen the internal structure of 'the macromolecular acrylic chains or to provide chemical functions: assisting in the fixation of the dyes, for example basic functions able to combine with the sulphonic or 'carboxylic gronps lof the solQuble orpseudo-soluble dyes. Among the products considered capable of being dyed may be mentioned theE fibres-or 2,937,067, Patented May 17,19 0

I threads with the following trademarks: Orlon (Du Pont de Nemours), Cr'ylor (Societ Rhodiacta), Pan (Cassella Farbwerke Mainkur), Dralon '(Farbenfabriken Bayer), Acrilan (Chemstrand Corporation), Dynel (Carbide & .Carbon Chemicals Corporation), Darlan (B.F. Goodrich Co.)

The colouration can be obtained by dyeing or printing. The dyeing can be carried out by known methods, either by circulating the bath, the material being stationary, or bypassing the material through the bath (vats, jigger, foulard) ,'or by employing apparatus which combines both movements. In order to reach a temperature above 100. 0., one can operate either .in an'aqueous bath open to the airwhose boiling point has been raised by the addition of soluble salts, or inan autoclave. When working on the foulardgthe fabric passesthrough the bath for some seconds and is then squeezed out between the rollers .of the. apparatus; thefixation of the dye is then carried out, with or without intermediate drying, by thermal treatment above 80 C.: the desired temperature is obtained by circulation of hot air, infra-red radiation,

contact with a heated metal, by steaming by means of steam at normal pressure or under pressure, or by treatment at a temperature above 80 C.-in an aqueous bath open to the airior under, pressure, or by any other suitable means. Printing of'thepolymers and copolymers inquestion can be carried out by means of the usualappa-ratusby.-the application of a paste containing a thickener; thefixation is effected by. one of the methods indicated above for foula'rded fabrics.

The num'ber of dyes, soluble, pseudo soluble or in soluble-in an aqueous medium, which can be applied according to the present process is large. By way of example, there may be mentioned: 1

(1) The acid dyes and the direct dyes. t

(2) The chromium complexes, called 1:1 that is, possessing one atom of. metal attached to one molecule of dye. These dyes are generally used for dyeing wool in a strongly acid bath or for dyeing polyamide fibres. (3) Metalliferous complexes, chiefly of chromium or cobalt, called 2:1, that is, possessing one atom of chromiprocess, the chromium dyes are :applied in the presence -of soluble metal salts, of chromium, iron, nickel, cobalt,

vanadium or manganese. It-does not matter if oxidis ing salts such as dichromates, chromates, or perman-y ganates are used which destroy the hydroxylamine. The complex can also-be previously prepared before the dye ing,.-by the action of the dye on the metal salt, isolation of the complex and use immediately for colouration; in

this case, it is not necessary to add a metal salt to the bathor the paste.

(-7;) .;The direct metallisable ,dyes; according to the present process these-direct dyes are appliedin the presence of soluble metal salts, of chromium, iron,'vanadiurn, nickel, cobalt, tin,-.-alumini um or manganese. It does not matter if oxidising salts which destroy the hydroxylamineareiused; The complexcan also bepi'eviviously'Ii: re1'izi1ied, beforethe' dyeing, "by the action of-the non-metallisable The metal 3 dye on the metal salt, isolation and use immediately for colouration; in this case, it is not necessary to add a metal salt to the bathor the paste.

(8) The leuco esters of vat dyes.

The dye baths or the printing pastes include the following elements: 7

The dye, the, hydroxylamine or one of its salts, such as the neutral sulphate, the acid sulphate, the hydrochloride, or the phosphate, and possibly the following products: soluble metal salts when the dye is not itself a metal complex, acids or alkalis intended to produce the pH conditions which are most satisfactory for the substance to be dyed, wetting and dispersing agents of anionic or non-ionic type intended to improve the wettability of the material, the uniformity of the dyeing and the dispersion of incompletely soluble dyes, swelling agents such as orthoor para-phenyl phenol, resorcinol, dimethylformamide,.soluble lithium salts, calcium thiocyanate, intended to facilitate the penetration of the dye into polymers which are difiicult to penetrate.

The colouration is effected by one of the previously mentioned processes of dyeing or printing at a temperature above 100 C. At l20l30 C. the results are always excellent and the bath is almost completely exhausted. The optimum temperature for the colouration is governed by the characteristics of the material to be coloured, which characteristics depend to a considerable extent on the method of manufacture of the latter. At the end of the dyeing or printing, it is expedient to subject the material to hot soaping, using soap or an anionic or non-ionic product, so as 'to purify the shade and remove particles of dye badly fixed on the surface.

The amounts of hydroxylamine or salt thereof and the amounts of metal salts vary according tothe depth of the shade and the bath ratio; in practice, however, they range from 0.5% to 10% based on the weight of the material to be coloured.

The present process allows not only dyes of the same group to be used in combination but also dyes of difierent groups, and even metalliferous dyes with metallisable dyes in the presence of metal salts. Dyes which are soluble and insoluble in an aqueous medium can also be used in combination. Finally, two or more salts of the same metal or different metals can be added when dyeing with metallisable dyes.

A modification of the process of this invention consists in adding to the dyebath or to the printing paste, not hydroxylamine or one of its salts, but products capable of giving them under the conditions of application. A nitrite, such as sodium nitrite, and sodium bisulphite may be used and an acid, such as sulphuric acid, added before the colouration. The action of the acid on the bisulphite liberates sulphur dioxide, which reduces the nitrite, or nitrous acid occasionally formed, to hydroxylamine. Nevertheless, the conditions for the colouration are not the optimum conditions for the preparation of hydroxylamine, so that the tinctorial yields are less than when hydroxylamine or one of its salts is added directly to the'bath.

Another variation of the process consists in adding hydroxylamine sulphate to the bath and liberating the base by the addition of sodium carbonate or a strong base, e.g. caustic soda or caustic potash.

The shades obtained are very varied and cover all those required in dyeing and printing; they display remarkable fastness both to light and to wet.or other treatments.

The examples which follow, which are not restrictive and in which the parts indicated are parts by weight, describe processes of colouration in accordance with the present invention.

EXAMPLE 1 v i droxylamine sulphate and 0.2 part of the 1:1 chromium complex of the dye obtained by coupling the diazo derivative of 6 nitro 2 amino 1 -hydroxy 4 benzenesulphonic acid with l-phenyl-3-methyl-5-pyrazolone.

.3:6- dinitro -2-aniinophenol naphthionic The temperature is raised to l20130 C. and dyeing is carried out at this temperature for three quarters of an hour to an hour. The fibres are rinsed and washed with soap in the hot. An orange colour is obtained.

Table I summarises some examples of dyeing carried out by the same process.

1 1 (4' -sulpho)phenyl3-methyl 5 pyra- 20 one.

2-amino-1:hydroxy-G-benzenesulphonic acid fl-naphthol.

4- chloro 2- amino 1 -hydroxy 6- benzenesulphonic acid 1 (4 sulpho)phenyl-3 ,-methyl- 5- pyrazolone.

1-amino2-hydroxy-4-naphthalene-sulphonic acid l-hydroxy-S-naphthalene sulphonic acid.

6-nitro-l-amino-2-hydroxy-4-naphthalene-sulphouic acid B-naphthol.

Reddlsh-brown.

Orange rod.

Grcenish blue.

Very dark grey.

Olive green.

Violet.

4 chloro 2 amino l hydroxy 6 -benzenesulphonic acrg 1-hydroxy-4-naphthalenesulphonic ac 4-chloro-l-amino-3 benzenesulphonic acid salicylic acid.

-chloro-2-amino-l-hydroxy-G-benzenesulphonic acid 2:4-dihydroxy-quinoline.

Yellow.

Reddish Bordeaux.

In this example one operates according to the process described in the first paragraph of Example 1, but instead of the dye mentioned in the latter exam-pie, one of those in Table 11 below is used. The latter dyes, denoted by the name under which they are known on the market, are 2:1 complexes of chromium or cobalt.

The edition of the Colour Index from which the corresponding dyes are cited is the 1956 edition.

Table II Colour on fibres based on- Dye copolymer of polyacryloacrylonitrile nitrile of the and vinyl Orion type chloride of the Dynel type Grey Cibalane BL (0.1. Acid Black 60) Bluish grey- Orange Ortolane R (0.1. Acid Orange 39). Orange Olive Irgalane BGL (0.1. Acid Black 64).. Olive Bggvn Lanasyne RL (0.1. Acid Brown 0hestnut Bgrgeaux Cibalane can or. Acid Red Bordeanx Cobalt complex of the dye: 2-amino-4-sul- Violet red.

phonamido-l-hydroxybenzene B-naphthol. OrIange N eopalatln GR (0.1; Acid Orange Orange Red Vialon test B (0.1. Acid Red 225 Red Red. Black Vialon last R (0.1. Acid Black 63) Very dark a 1 y Yellow Vialon fast R (0.11. Acid Yellow Reddish 119). I 1 yellow Green Sirius Light FFGLU/ EXAMPLE '3 .In this example one operates as indicated in Example 1, but replacing the complex used by the copper complex of the dye obtained by coupling the tetrazo derivative of dianisidine with one molecule of l-hydroxy-naphthalene- 3:8-disulphonic acid and one molecule of 6-phenylamino- 1-hydroxy-3-naphthalenesulphonic acid. A navy .blue colour is obtained. Table III below summariseszsome examples of colours obtained with the metalliferous polyazo dyes according to the same process; these dyes are denoted by the commercial names under which they are known on the market.

Table III Colour obtained on polyacrylonitrile fibres Metalliferous polyazo dye pr Orlon of Crylor W1 EYD Brown Diazole Light BRN (C.I. meet chestnut... yellowish vBrown 95). brow n. BliCiWn Diazole Light 8RL (C.I. Direct Brown red-brown red brown. Ruby Diazole Light 2BL (C.I. Direct Red 83) brown-red brown-red. Grey Diazole Light 6BL (C.I. Direct Black 71)- yellowish grey. veg ie Diazole Light BLN (C.I. Direet Violet blue-grey. Ruby Ohlorantine Light ELL; ruby It is also possible to operate as has just been indicated by adding to the dye bath 0.8 to 1 part of sodium carbonate in order to liberate the hydroxylamine. According to this process there is obtainedwith the Brown Diazole Light BRN a yellowish brown colour on -a polyacrylonitrile fibre of the Orlon type.

a In this example-one operates as indicated in the first paragraph of Example 1, but the dye of Example 1 is replaced by the disulphonated derivative of copper phthalocyanine, known under the trade'na'me of THE, quoise Diazole Light JL (C. I. Direct BlueSG). green colour having excellent vfastness to light andgto washing is obtained. g

- Table IV below summarises some examples..- carried out by the same process with analogous dyes; thesedyes; are denoted by the names under which they are known on the market.

T able IV Colour on polyacrylonitrile fibre of the ,Orlon' type Dye Green. Alcian blue 8 GS Blue Zapon last HFL (C.I Solvent Blue 25)..

,Brilliant Blue lndanthrene ,-4G (C.I. Vat Blacks applied according to the sameprocess'inthe form'of the,

leuco derivative in the presence of hydrosulphite and caustic soda gives a greenish blue colour.

Brilliant. Green Sulfogene J (C.I. SulphurGreen: 14)

is applied by reduction and solubilisation of the dyeljin an alkaline sulphide medium in the following mgslnner.v

0.2 part of concentrated settled sodium sulphide is mixed with 0.2 part ofdye, 5 parts of pure boiling waterare added'and the' mixture is stirred for to 15 vminutes to allow'the-reductiori of the'dye and'itsfjsolubilisation to take place." This'solution ispou'red into a bath compris A'ia turquoise blue. blue. w V

,' one operates as indicated in thelirst paragraph ing" 195 parts of 'v'vat'en'on'e part of hyd'roxylaminesul;

phate, and 0.3part'ofs6dium carbonate. 10 parts er" polyabrylonitrile fibre of Orlon type are introduced and Violet Diazole BS (C.I. Direct Violet 22) of Example 1. A dark green colour is obtained. vFinely dispersed copper phthalocyanine is applied in the following way: 0.2 part of dye is made into a paste with one to two parts of hot water, and 20 parts of hot water are added. The dispersion obtained is Pouredinto a bath comprising parts of water and one part of hydroxylamine sulphate. 10 parts of polyacrylonitrile fibre of Orlon type are introduced and one operates as indicated in the first paragraph of Example 1. Arturquoise blue colour is obtained.

EXAMPLE 5 In this example one operates as'in the first paragraph of Example 1, but the dye of Example 1 is replaced by. the dye obtainedby coupling the diazo derivative of aniline with 1-(4'-chloro-6'-sulpho)phenyl 3-methyl 5-V pyrazolone, and in addition to hydroxylamine sulphate,

0.2 part of a soluble non-oxidising chromium salt, such as chromium fluoride or acetate, is-added to the dye bath. An orange-red colour is obtained.

1 Table V summarises some examples of dyeing carried out by this process with other mordant dyes called chrome dyes. l v

In thisexample one operates according to the process described in the first paragraph of Example 1, but the dye of Example 1 is replaced by one of those known on the I market under thennames mentioned in the following able:- .1

Table VI 1' i Colour on poly- I acrylonitrile .Orlon type Dye Fast bordeaux DiazoleBB (C.I. Direct Red 16)"- Brown Diazole M (C.I. Direct Brown 2) Blue Diazole 3R (C.I. D rect Blue 3),.-. blue. Black Diazole ER (C.I. Direct Black 4) very dark'grey. Orange Cuprodiazole Light BR (C.I. Direct Orange 98). oran t EXAMPLE '7 v e In this example one operates according to the process described in ;,the first paragraph of- Example 1, but the dye of Example-;1;'is replaced by oneof'those known on e-mer etvnd the nam s ment ne in the f ll w table.

salt to the dye bath.

Colour on poly- Dye acrylonitrilo fibre f Orlon type yellow.

re very dark grey. orange. brown.

orange yellow. green.

bright yellow. violet.

orange. yellow. Do.

Supe Chrysoine (C.I. Acid Orange 6) A. Alizarin green .1 (0.1. Acid Green 25) Foulon yellow 7.1L (C.1. Acid Yellow 44) Foulon violet S 2B (0.1. Acid Violet 72)- Acid yellow light H (0.1. Acid orange 3). Superacid yellow 5.1L 0.1. Acid Yellow 22)- Pyrazolone yellow 3.1 (0.1. Acid Yellow 37)-... Xylene orange L (C.L. Foulon Scarlet R (C.I. Superacid brown R (0.1. Acid Brown 35).-- Fast Acid green BL (0.1. Acid Green 31) Alizarin Cyanine green 50 (0.1. Acid Green Acid Alizarin sky blue B (0.1. Acid Blue 78)- orange.

red.

Alizarin sapphire SE (0.1. Acid Blue 4 Do. ast Cyanine brilliant I L (0.1. Acid Blue 101) Do. Fast Cyanine brilliant BL (0.1. Acid Blue 59) 'Do. Orange 11 (0.1. Acid Orange orange. Foulon orange R (0.1 Acid Orange 79).-- D0. Fast Acid red BRL (0 I Acld Red 118) red. Fast Acid red 43L (0.1 Acid Violet 14) violet red. Superacid red 2.1 (0.1. Acid Orange 19); red. Superacid red I (0.1. Acid Red 181). Do; Foulon red I (0.1. Acid Red 85) Do.

EXAMPLE 8 In this example one operates as indicated in the first paragraph ofExample 5, the soluble chromium salt being replaced by stannous chloride. A bright yellow colour is obtained.

The colours obtained with the same dye in the presencev of other soluble metal salts are indicated in Table VIII below:

Table VIII Colour obtained Metal salt on polyacrylonitrile fibre oi the Orion type Nickel acetate reddish orange. Cobalt nitrate Do. Aluminium snlnhatp orange yellow. Manganese sulphate yellow. Ferrous sulnhdte beige.

EXAMPLE 9 In this example one operates as in Example 5, the dye of Example 5 being replaced bya direct copperable dye, for example, the dye l-hydroxy-Z-amhao--chloro urea of 3' acid l-hydroxy-2-amino-4-chloro and the soluble chromium salt being replaced by stannous chloride. A chestnut colour is obtained.

In the presence of one of the soluble metal salts enu-' merated in Table 1X below, the same dye gives the following colours:

EXAMPLE 10 In this example, the metalliferous complex of a metal;

lisable dye previously prepared before dyeing, isused. In this case therefore, it is not necessary to add ametal This metallic complex'is prepared as follows: a solution of 10 parts of the so-called chrome dye described in the first paragraph of Example 5 in 100 parts of water is treated with a solution of 5 to- 20 parts of a soluble metal salt, such as stannous chloride, in 50 to 100 parts of water. The precipitate instantaneously formed is filtered off on a Buchner funnel, washed with distilled watcr to remove excess metal salt or dye which has not formed acomplex, and dried.

In order to dye polyacrylonitrile fibres, the procedure of Example 1 is used, the dye of Example 1 being replaced by the metalliferous complex prepared as above. A bright yellow colour is obtained.

EXAMPLE 11 In this example one operates as in Example 1, with the hydroxylamine sulphate being replaced by the mixture of the following constituents:

1 part of sodium nitrite 20 parts of sodium bisulphite (28 B. solution) 2 parts of concentrated sulphuric acid A cream colouris obtained.

' EXAMPLE 12 10 parts of fibres based on polyacrylonitrile are introduced into a bath comprisingZOO parts of water and one part of hydroxylamine sulphate. The temperature is raised to 120-130 C., and is kept at this for three quarters of an hour to one hour. The fibres so treated are rinsed in water and introduced, into a bath made up of 200 parts of water and 0.2 part of the dye used in Example 1. The temperature is taken to 120-130" C. and dyeing carried out at this temperature for three quarters of an hour to one hour. The fibres are rinsed and washed with soap in the hot. An orange colour isobtained. a

EXAMPLE 13 (a) A strip of polyacrylonitrile fabric of Orlon type is passed into a foularding bath containing the dye used in Example 1 and hydroxylamine sulphate in a ratio of 5 parts of hydroxylamine sulphate to one part of dye.

.After foularding, the fabric is squeezed out in such a way that one can fix 0.2 part of dye and 1 part of hydroxylamine sulphate for 10 parts of fabric. I

The fabric is then introduced into a bath consisting of 200 parts of water. The temperature is taken to -130 C. and kept at this for about three quarters of an hour.

The fabric is rinsed and washed with soap in the hot.',

An orange colour is obtained.

(b) Foularding is effected in the same manner as in, (a) and the fabric is steamed forhalf an hour at normal pressure (102l03 C.). With or without intermediate drying, an organge colour is obtained.

7 (c) Foularding is eifected in the same manner asinv (a) and the fabric is steamed for half an hour under.

pressure (at 0.); with or without intermediatedrying, an orange colour is obtained. 7

(d) Foularding is effected in the same manner as in (a) and the fabric is left for half an hour in a chamber heated to a temperature of 0.; with or without intermediate drying, a yellowish orange colour is obtained;

EXAMPLE 14 washing with soap in the hot, a reddish orange colouris obtained.

EXAMPLE 15 Operating according to the process described in Example 14, (a) and (b), but replacing the dye of Example 14 by that described in Example 3, a violet blue colour is obtained by the variant (a) and a navy blue colour by the variant ([1).

EXAMPLE 16 In this example one operates according to the process described in Example 14 under (a) and (b) but with a paste having the following composition:

10. EXAMPLE 19' On operating as in Example 4, and using the follow-J ing quantities of dye and hydroxylamine sulphate:

(a) 0.4 part of dye and 2 parts of hydroxylamine sulphate: a'dark jade green is obtained.

(b) 0.02 part of dye and 0.5 part of hydroxylamine sulphate; a pastel greenis obtained.

EXAMPLE 20 On operating as in Example 1, and replacing the dye of Example 1 by a mixture of the following dyes:

0.1 part of the dye used in Example 4, and 0.1 part of the dye used in Example 5 and adding 0.2 part of stannous chloride to the dye bath, a bright yellow green is obtained.

EXAMPLE 21 In this example one operates according to the process described in Example 1, the dye of Example l-being replaced by one of those known on the market by the names mentioned in Table X below:

7 Parts Dye used in Example 5 3 25 Glycerine 5 Table X Hydroxylamine Sulphate 5 Chromium acetate at 20 B 9 c ouromam H011 water 18 Dye ac lg iii ile Starch-tragacanth thickener 50 limos 100 Sogsfil Brilliant Yellow $18 0.1. Solubilised Vat yellow. e ow A brownish red colour is obtained with or without 5031501 Bbilliant Yellow RS (0.1. Solubilised Vat orange. range mtermedlate drymg' Solasol Orange RH (0.1. Solubllised Vat Orange 5) Do.

Solasol Brilliant Rose RS (0.1. Solubilised Vat Red 1). red. EXAMPLE 17 soxl aiscllltll3fllliant Violet 4 RS (0.1. Solubilised Vat violet.

O 8 o Solasol Blue SBS (0.1. Solubilised Vat Blue 6 blue.

10 parts f polyacrylomtnle f O l type, m sogrsgnlgprk Green IS extra (0.1. Solliblllsed Vat green. the f rm of fabric, are introduced into a bath consist- Solasol Brown BRS (0.1. Solubilised Vat Brown 1) brown. ing of 200 parts of water and one part f h d l- 40 Solasol Bl0W112RS(C.I.-S0lllbl1]S8d Vat Brown 5)..-. Do. amine sulphate. The temperature is taken to 120-130 C. and kept at this for three quarters of an hour to an We claim:

hour. The fabric thus treated is rinsed in hot water and dried in hot air. Printing is effected by the process described in Example 14 under (a), using a paste of the same composition. An orange colour is obtained by steaming at normal pressure (102103 C.) or under pressure (130 C.).

(b) Operating according to the process described under (a), but replacing the polyacrylonitrile of Orlon type by a product from the copolymerisation of acrylonitrile and vinyl acetate or vinyl pyridine, known-by the commercial name of Acrilan, a brownish orange colour is obtained by steaming at normal pressure (102- 103 C.) or under pressure (130 0.).

EXAMPLE 18 A piece of polyacrylonitrile fabric of Orlon type is printed by the roller process, with a paste having the following composition:

The fabric is steamed for half an hour either at normalpressure (102-l03 C.) or under pressure (130 C. a reddish orange colour being obtained.

1. A process for colouring a synthetic material selected from the group consisting of the polymerisation products of acrylonitrile, the copolymerisation products of acrylonitrile, the polymerisation products of vinylidene cyanide and the copolymerisation products of vinylidene cyanide, which comprises simultaneously treating the synthetic material at above C. with (1) a dye selected from the group consisting of the acid non-metallisable dyes, the direct non-metallisable dyes, the chromiferous dyes as 1:1 complexes, the metalliferous dyes as 2:1 complexes, the complexesof polysulphonated monoazo dyes and copper from the class of direct dyes, the complexes of the sulphonated polyazo dyes and copper from the class of direct dyes, the phthalocyanines, the derivatives of phthalocyanines, the chrome dyes (mordant dyes), the direct metallisable dyes and the leuco esters of vat dyes, and with (2) a member selected from the group consisting of hydroxylamine and its salts.

2. A process as claimed in claim 1 in which the dyeing is efiected with a metallisable dye selected from the group consisting of the chrome dyes (mordant dyes), and the direct metallisable dyes, in the presence of a salt of a metal selected from the metals of the group consisting of chromium, iron, nickel, cobalt, tin, aluminium and manganese.

3. A process as claimed in claim 1 in which hydroxylamine is replaced by a mixture capable of providing it, comprising sodium nitrite, sodium bisulphite and an acid.

4. A process as claimed in claim l'in which the amount of the member selected from the group consisting of hydroxylamine and its salts is from 0.5% to 10% based on the weight of synthetic material.

11 5. A process as claimed in claim 2in which the amount FOREIGN PATENTS of the metal salt is from 0.5% to 10% based on the 1,094,620 France May 23, 1955 weight of synthetic material.

OTHER REFERENCES References Cited in the file of this patent 5 A Schouteden, Melland, vol. 38, January 1957, pp. 65-68. UNITED STATES P TENTS Skinkle: Amer. Dyestufi Rep., vol. 46, No. 19, Sept. 2,792,276 Kaupin May 14, 1957 23, 1957, pp. 706-708. 

1. A PROCESS FOR COLOURING A SYNTHETIC MATERIAL SELECTED FROM THE GROUP CONSISTING OF THE POLYMERISATION PRODUCTS OF ACRYLONITRILE, THE COPOLYMERISATION PRODUCTS OF ACRYLONITRILE, THE POLYMERISATION PRODUCTS OF VINYLIDENE CYANIDE AND THE COPOLYMERISATION PRODUCTS OF VINYLIDENE CYANIDE, WHICH COMPRISES SIMULTANEOUSLY TREATING THE SYNTHETIC MATERIAL AT ABOVE 100*C. WITH (1) A DYE SELECTED FROM THE GROUP CONSISTING OF THE ACID NON-METALLISABLE DYES, THE DIRECT NON-METALLISABLE DYES, THE CHROMIFEROUS DYES AS 1:1 COMPLEXES, THE METALLIFEROUS DYES AS 2:1 COMPLEXES, THE COMPLEXES OF POLYSULPHONATED MONOAZO DYES AND COPPER FROM THE CLASS OF DIRECT DYES, THE COMPLEXES OF THE SULPHONATED POLYAZO DYES AND COPPER FROM THE CLASS OF DIRECT DYES, THE PHTHALOCYANINES, THE DERIVATIVES OF PHTALOCYANINES, THE CHROME DYES (MORDANT DYES), THE DIRECT METALLISABLE DYES AND THE LEUCO ESTERS OF VAT DYES, AND WITH (2) A MEMBER SELECTED FROM THE GROUP CONSISTING OF HYDROXYLAMINE AND ITS SALTS. 